# CVE-2026-67216: cJSON cJSON_Compare Exponential Complexity Denial of Service

> An attacker can cause a denial of service by providing deeply nested JSON to cJSON_Compare, leading to exponential CPU consumption.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Jul 2026
- **Updated:** 30 Jul 2026
- **Also known as:** AZL-94407, DEBIAN-CVE-2026-67216, ECHO-a8fe-5bd2-dfa4, GHSA-ff2v-f99f-wm3f, ROOT-OS-ALPINE-321-CVE-2026-67216, ROOT-OS-ALPINE-323-CVE-2026-67216, UBUNTU-CVE-2026-67216

## What is CVE-2026-67216?

CVE-2026-67216 is a high-severity denial of service vulnerability in DaveGamble cJSON, published on 29 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-67216?

It affects 1 product.


Products: Davegamble Cjson.

## How do I fix CVE-2026-67216?

Upgrade to a fixed version.

## Is CVE-2026-67216 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67216 exists.

## Other vulnerabilities in DaveGamble cJSON

- [CVE-2025-57052](https://insights.sbomify.com/CVE-2025-57052/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-11834](https://insights.sbomify.com/CVE-2019-11834/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-11835](https://insights.sbomify.com/CVE-2019-11835/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-10749](https://insights.sbomify.com/CVE-2016-10749/): Memory corruption in n/a (critical 9.8)
- [CVE-2018-1000217](https://insights.sbomify.com/CVE-2018-1000217/): Use after free in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-67216 and fix it if it is affected.

What it is: CVE-2026-67216 is a high-severity denial of service vulnerability in DaveGamble cJSON, published on 29 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67216 exists.

Affected product: DaveGamble cJSON. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-67216/ (Markdown: https://insights.sbomify.com/CVE-2026-67216/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67216
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67216
- OSV: https://osv.dev/vulnerability/CVE-2026-67216

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-67216/
Summaries are generated and may contain mistakes; the official description above is the record.